Writing with pen and paper has following advantages
It costs almost nothing to buy pen and paper. You can possibly get them free from your work or school.
Writing on paper with a pen is much faster than writing on touch screen devices either with a stylus or finger.
They will last longer than digital notes. Traditional handwritten notes last well beyond 20 years if preserved with sufficient care. But you never know when new technology will make your ddigital note obsolete any day. Also with paper notes you don't need to think about having same hardware and software when you need to amend them!
No one will steal your paper notes!
If you really need to digitise your notes, you can always scan them and get them into computer.
If you already have a tablet, then probablynit makes sense to type the note in the first place.